Part A
0451007.MRL
リテルヒューズ社
- Lifecycle
- Active
- Stock
- 4553 個数
- Package
- 2-SMD
- Series
- ヒューズ
Replacement verdict
Compatible functional replacement candidate
The 0451001.MRL and 0451007.MRL are both fast-acting surface-mount fuses from the Littelfuse 451 series, sharing the same 1206 footprint, voltage rating, and interrupting capacity. The primary distinction is the current rating, with the 0451001.MRL rated at 1A and the 0451007.MRL rated at 7A. Because the current ratings differ significantly, the 0451007.MRL should not be used as a direct substitute for the 0451001.MRL in circuits designed for 1A protection, as this would compromise overcurrent protection. However, both parts are functionally compatible in terms of package, form factor, and electrical characteristics, making them suitable candidates for applications where the respective current rating is appropriate.
Current Rating
Validation required
Package Type
High match
Voltage Rating
High match
Interrupting Capacity
High match
Parts at a glance
Part B
0451001.MRL
リテルヒューズ社
- Lifecycle
- Active
- Stock
- 7334 個数
- Package
- 2-SMD
- Series
- ヒューズ
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 0451001.MRL | 0451007.MRL | Why it matters |
|---|---|---|---|
| Current Rating | 1 A | 7 A | Determines the maximum continuous current the fuse can carry without opening; a functional substitute must match or exceed the circuit's operating current. |
| Voltage Rating | 125 VAC / 125 VDC | 125 VAC / 125 VDC | Must be at least equal to the circuit voltage to ensure safe interruption of fault currents. |
| Interrupting Rating | 50 A at 125 VAC / 300 A at 125 VDC | 50 A at 125 VAC / 300 A at 125 VDC | Defines the maximum fault current the fuse can safely clear without rupturing or arcing. |
| Melting I²t | 0.42 A²s | 21.5 A²s | Indicates the energy required to open the fuse; affects coordination with inrush currents and downstream protection. |
| Nominal Cold Resistance | 0.145 Ohms | 0.0105 Ohms | Lower resistance reduces voltage drop and power loss; a substitute with higher resistance may cause excessive heating or voltage sag. |
| Voltage Drop at Rated Current | 0.145 V | 0.0735 V | Directly impacts circuit efficiency and heat generation; must be compatible with the application's tolerance. |
| Fuse Type | Fast-Acting (Nano2) | Fast-Acting (Nano2) | Fast-acting vs. time-delay behavior determines response to transient currents; mismatches can cause nuisance blowing or delayed protection. |
| Package / Size | Nano2 SMF (6.1 mm x 2.69 mm) | Nano2 SMF (6.1 mm x 2.69 mm) | Physical footprint and mounting style must match the PCB layout for drop-in substitutability. |
| Operating Temperature Range | -55°C to +125°C | -55°C to +125°C | Ensures reliable operation and correct derating across the application's environmental conditions. |
| Approvals / Standards | UL Recognized, CSA Certified, PSE | UL Recognized, CSA Certified, PSE | Safety agency approvals are required for end-product certification and indicate compliance with recognized standards. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 0451007.MRL | 0451001.MRL |
|---|---|---|
| Series | NANO²® 451 | NANO²® 451 |
| Part Status | Active | Active |
| Mounting Type | Surface Mount | Surface Mount |
| Fuse Type | Board Mount (Cartridge Style Excluded) | Board Mount (Cartridge Style Excluded) |
| Current Rating (Amps) | 7 A | 1 A |
| Voltage Rating - AC | 125 V | 125 V |
| Voltage Rating - DC | 125 V | 125 V |
| Response Time | Fast Blow | Fast Blow |
| Breaking Capacity @ Rated Voltage | 50A | 50A |
| Melting I²t | 10.32 | 0.459 |
| Approval Agency | CSA, PSE, UL | CSA, PSE, UL |
| Operating Temperature | -55°C ~ 125°C | -55°C ~ 125°C |
Frequently asked questions
What are the 0451001.MRL and 0451007.MRL fuses?
The 0451001.MRL and 0451007.MRL are surface-mount fuses from Littelfuse's 451 series, designed for overcurrent protection in electronic circuits. The 0451001.MRL is rated 1 A and the 0451007.MRL is rated 7 A, both with a voltage rating of 125 V AC/DC and a breaking capacity of 50 A at 125 V AC/DC.
What is the main difference between the 0451001.MRL and 0451007.MRL?
The primary difference is the current rating: the 0451001.MRL has a rated current of 1 A, while the 0451007.MRL has a rated current of 7 A. Both share the same 451 series platform, including the same physical package, voltage rating, and interrupting rating.
Are the 0451001.MRL and 0451007.MRL physically interchangeable?
Yes, both fuses use the same surface-mount package footprint and body dimensions within the Littelfuse 451 series, so they are mechanically interchangeable on a compatible PCB land pattern. However, electrical suitability must be verified for the target application.
Can the 0451001.MRL be replaced by the 0451007.MRL in a circuit?
No, not as a direct substitute. The 0451007.MRL has a higher current rating (7 A versus 1 A), which changes the overcurrent protection threshold and may fail to protect the downstream circuit as intended. Replacement must be evaluated against the design's required trip current and fault conditions.
What are the voltage and breaking capacity ratings for these fuses?
Both the 0451001.MRL and 0451007.MRL are rated for 125 V AC/DC with a breaking capacity of 50 A at 125 V AC/DC, as specified in the Littelfuse 451 series datasheet.
Do the 0451001.MRL and 0451007.MRL have the same time-current characteristics?
Both are fast-acting fuses within the Littelfuse 451 series, so they share the same time-current curve family. However, because their current ratings differ, the absolute trip times at a given fault current will differ according to the respective rating.
What are the typical applications for the 0451001.MRL and 0451007.MRL?
These fuses are typically used for overcurrent protection in space-constrained surface-mount applications such as battery packs, power supplies, and portable electronics. The 0451001.MRL suits lower-current rails, while the 0451007.MRL suits higher-current rails within the 451 series ratings.
Are the 0451001.MRL and 0451007.MRL RoHS compliant?
Yes, both the 0451001.MRL and 0451007.MRL are RoHS compliant and lead-free, as stated in the Littelfuse 451 series datasheet and product documentation.